You may freshen up your breath, but cops will soon be equipped with a microphone that can catch you by your voice pattern
CATCHING sloshed people on the roads has always been tricky for the police. Mild drinkers are often experts at pretending that they are sober. But the next time you get caught for driving in an
inebriated state, the cops may simply
ask you to speak in a microphone linked
to a computer, which can easily provide
conclusive proof of your crime (The
Economist, Vol339, No 7969).
An American scientist, Kathleen
Cummings from the Georgia Institute
of Technology in Atlanta, us, is developing a new technology that can elicit patterns from drunken speech that a computer can analyse. In a related work,
researchers Renetta tull and Janet
Rutledge from the Northwestern
University in Evanston, Illinois, are
examining what having a cold can do to
your voiceprint -their efforts aim
towards discovering the gadgets that a
computer would need to separate one
person's voice from another's.
A lot of research in speech recognition is already underway. It basically
means picking out the voiceprint -the
elements that make a voice unique and
hence recogniseable. It also enables
recognition of a person's voice with a
bunged-up nose or alcohol-sodden consonants.
The human voice, as we hear it, is
born in the vocal cords, and is then
modified and articulated in the vocal
tract ~ the throat, mouth and lips. For
a computer to recognise a human voice,
it needs to <;onvert the="" sound="" into="" mathematical="" formulae.="" there="" are="" several="" ways="" of="" doing="" it,="" each="" highlighting="" different="" aspects="" of="" the="" voice.="" the="" first="" is="" the="" raw="" sound="" -the="" waveform.="">;onvert>
To unpack this waveform,
Cummings passed a speech recording
backwards through a series of filters that
mimic the vocal tract, returning it as
closely as possible to the pristine glottal
sound. She found that a drunken person not only walks unsteadily but also has
wavering vocal cords - this enables a
reliable computer test for intoxicated
speech. Similarly, Tull and Rutledge put
snuffy and normal voice recordings
through another filter - one that simulates how human hearing systems
process sound. They found that healthy
and unhealthy voices contained different features which could be measured
by a computer.
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